In recent years, in order to ensure a safety of a passenger at a time where a vehicle collides, a standard is set in an in-vehicle equipment such as a car-mounted navigation apparatus and a car audio apparatus and various instruments incorporated in an instrument panel in a vehicle compartment so that an operating knob does not harm the passenger. For example, Rule No. 21 of ECE (Economic Commission for Europe) requires that the operating knob is sunk so that a protruding amount of the operating knob is within a certain amount when a load greater than or equal to 378 [N] is applied to the operating knob from an exterior in a direction toward an encoder (i.e., in a sinking direction).
U.S. Pat. No. 7,251,861 (corresponding to JP-2004-338427A) discloses an operating knob that includes a plurality of crushable connecting elements provided from a rotation axis of an encoder toward an outer circumferential side. When a load is applied to the operating knob from an exterior in the sinking direction, the crushable connecting elements are crushed, and thereby the operating knob is sunk.
In the present configuration, when a size of the operating knob becomes large, there is a possibility that the crushable connecting elements are not crushed evenly depending on a direction in which the load is applied. If the crushable connecting elements are not crushed evenly, there is a disadvantage that the crushable connecting element that has not been crushed may remain, and thereby the operating knob may not sink or the operating knob may sink obliquely.
Alternatively, JP-2001-266704A discloses an operating knob that includes shock-absorbing projections. The shock-absorbing projections are provided at a through shaft-hole portion and function as stoppers. When a load is applied to the operating knob from an exterior in the sinking direction, the shock-absorbing projections are crushed and are separated. Thereby, the operating knob is sunk.
In the present configuration, a space for housing the separated shock-absorbing projections is required in the sinking direction. In addition, there is a possibility that the separated shock-absorbing projections are caught. If the separated shock-absorbing projections are caught, also in the present case, the operating knob may not sink or the operating knob may sink obliquely.